Wellbore servicing fluid comprising a cellulose ether

Abstract

A cellulose ether having (i) one or more substituents selected from the group consisting of methyl, hydroxyethyl and hydroxypropyl, (ii) one or more hydrophobic substituents, and (iii) one or more cationic, tertiary amino, or anionic substituents, and having a retained dynamic viscosity, %η 80/25 , of at least 30 percent, wherein %η 80/25 =[dynamic solution viscosity at 80° C./dynamic solution viscosity at 25° C.]×100, the dynamic solution viscosity at 25° C. and 80° being measured as 1% aqueous solution, is useful for modifying the viscosity of a composition selected from the group consisting of wellbore servicing fluids, cementitious formulations, ceramics, metal working fluids and cutting fluids.

What is claimed is: 
     
       1. A cellulose ether having
 (i) one or more substituents selected from the group consisting of methyl, hydroxyethyl and hydroxypropyl, 
 (ii) one or more hydrophobic substituents consisting of acyclic or cyclic, saturated or unsaturated, branched or linear alkyl hydrocarbon groups having at least 8 carbon atoms, and 
 (iii) one or more cationic, tertiary amino, or anionic substituents, and having a retained dynamic viscosity, %η 80/25 , of at least 30 percent, wherein
   %η 80/25 =[dynamic solution viscosity at 80° C./dynamic solution viscosity at 25° C.]×100,
 
 
 
       the dynamic solution viscosity at 25° C. and 80° being measured as 1% aqueous solution. 
     
     
       2. The cellulose ether of  claim 1  having one or more cationic substituents of the formula I 
       
         
           
           
               
               
           
         
         wherein 
         R 1 , R 2  and R 3  each independently are CH 3 , C 2 H 5 , or C 3 H 7 , 
         R 4  is CH 2 —CHOH—CH 2 — or CH 2 CH 2 —, 
         A z−  is an anion, and z is 1, 2 or 3. 
       
     
     
       3. The cellulose ether of  claim 1  having one or more sulfo-C 1-6 -alkyl groups. 
     
     
       4. The cellulose ether of  claim 1  having one or more carboxymethyl or carboxyethyl groups. 
     
     
       5. The cellulose ether of  claim 1  having one or more dimethylamino, diethylamino, or diisopropylamino groups. 
     
     
       6. The cellulose ether of  claim 1  having a Brookfield viscosity of at least 20,000 mPa-sec, measured as 1% aqueous solution at 6 rpm, spindle 4 at 25° C. 
     
     
       7. The cellulose ether of  claim 1  having a weight average molecular weight of at least 750,000. 
     
     
       8. The cellulose ether of  claim 1  having a retained dynamic viscosity %η 80/25  of at least 35 percent. 
     
     
       9. The cellulose ether of  claim 1  wherein the average level of substitution with said one or more hydrophobic substituents is from 0.007 to 0.025 moles per mole of anhydroglucose unit. 
     
     
       10. The cellulose ether of  claim 1  having a hydroxyethyl molar substitution of from 1.5 to 3.5. 
     
     
       11. A composition selected from the group consisting of wellbore servicing fluids, cementitious formulations, ceramics, metal working fluids and cutting fluids comprising a cellulose ether having
 (i) one or more substituents selected from the group consisting of methyl, hydroxyethyl and hydroxypropyl, 
 (ii) one or more hydrophobic substituents, and 
 (iii) one or more cationic, tertiary amino, or anionic substituents. 
 
     
     
       12. The composition of  claim 11  comprising the cellulose ether of  claim 1 .